A compilation of the latest data on extinction rates of plant and animal life around the world reports that humanity's impact on the earth has increased extinction rates to levels rivaling the five mass extinctions of past geologic history.

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ST. LOUIS, MO, August 2, 1999 -- A compilation of the latest data on extinctionrates of plant and animal life around the world reports that humanity's impacton the earth has increased extinction rates to levels rivaling the five massextinctions of past geologic history. The paper was released today by thePresident of the International Botanical Congress, Peter Raven, PhD, who is aworld leader in plant conservation. It predicts that between one-third andtwo-thirds of all plant and animal species, most in the tropics, will be lostduring the second half of the next century. The paper calls for an eight-pointplan to arrest species loss within plant ecosystems.

"Human efforts have been notable for their lack of attention to the living worldthat supports us all," said Raven, who is also Director of the MissouriBotanical Garden. "In the face of the worldwide extinction crisis, we shouldredouble our efforts to learn about life on Earth while it is still relativelywell represented."

More than 4,000 scientists from 100 countries are meeting at the InternationalBotanical Congress this week to discuss the latest results of research on plantsfor human survival and improved quality of life. Raven's remarks were made at apress briefing held prior to the "Millennium Symposium," where the paper,"Plants in Peril: What Should We Do?" will be formally presented to theCongress.

Over the past several centuries, the documented extinction rates of a wide rangeof well-known groups of organisms are several times higher than the backgroundrate or rate at which species have been becoming extinct for the past 65 millionyears, since the major extinction event that closed the Cretaceous Period andthe Mesozoic Era, which coincided with the loss of the last surviving dinosaurs.This was the fifth major extinction event in Earth history, a time whentwo-thirds of all terrestrial organisms that lived at that time disappeared andthe character of life changed permanently. The current extinction rate is nowapproaching 1,000 times the background rate and may climb to 10,000 times thebackground rate during the next century, if present trends continue.

According to the paper, species loss can be estimated even when the members ofmany groups of organisms are relatively poorly known because of the logarithmicrelationship between species number and the area in which they live. On theaverage, a tenfold increase in area is correlated with a doubling in speciesnumber, and a tenfold decrease with a halving of the original number. Given therelationship between species number and area, one can determine the number ofspecies that will survive in a given area. Fragments of a given habitat thathave been reduced in size lose half of the species they are going to lose inabout 50 years; three-quarters of them in a century.

The paper states that if current trends continue, and we retain just fivepercent of tropical forests in protected areas, which will be true within 50years at present rates of destruction (and sooner if these rates areaccelerated), then extinction rates will be three or four orders of magnitudehigher than those prevailing between mass extinctions. At this rate, one-thirdto two-thirds of all species of plants, animals, and other organisms would belost during the second half of the next century, a loss that would easily equalthose of past extinctions.

The paper states that vast numbers of unknown plants, animals, and otherorganisms are currently being lost before they've been recognized. Only about1.6 million organisms out of a conservative estimate of between seven and 10million have been recognized scientifically. A great majority of these arepoorly known, often from a single specimen, a brief description, a locality,nothing more, according to the paper. Some 250,000 of 300,000 species of plantshave been identified, leaving some 50,000 completely unknown.

The extreme depletion of genetic variation in individual plant species causesthem to become more vulnerable to extinction, according to the paper.Genetically diverse traits in plants can often enable them to grow in harsherenvironments, for example, or survive the competition with weedy species. About30 percent of the world's 300,000 plant species are in cultivation now, "whichprovides a good start for conservation," according to Raven.

The paper outlines an seven-point plan to slow the extinction rates of plantsaround the world. It suggests that a major United Nations-sponsored conferenceon this topic could move these steps into country-by-country actions.

"All plants are important in one way or another and this comprehensive planseeks to save them all -- a priceless gift to future generations," said Raven.

Establish a new coordinating body -- presumably connected with the UnitedNations directly or through one of its constituent organizations -- to monitorthe status of plants throughout the world, detect those most in danger, and takesteps to conserve them.

"There are a number of organizations working effectively in plant conservationnow that could benefit greatly from the kind of overall internationalcoordination that such a global body could provide," said Raven. "Theseorganizations include, but are not limited to, Botanic Gardens ConservationInternational and the Plant Conservation Program of the World ConservationUnion's Species Survival Commission."

Increase financial support for the study of plants throughout the world bothby strengthening the major museums and other institutions that have holdings ofspecimens and literature on plants and by capacity building in developingcountries with scarce resources. Currently, 80 percent of the world's scientistslive in industrialized countries, which have about 20 percent of the world'spopulation and only 20 percent of the world's biodiversity.

"Nations will only preserve biodiversity if they have their own institutions andtheir own scientists to make recommendations about what's best for them," saidRaven.

The paper calls for the Convention on Biological Diversity (CBD) and the GlobalEnvironment Facility (GEF) to step their efforts train scientists.

Make information on plants -- now only available in herbarium, arboreta, seedbanks, universities, and botanical gardens -- accessible on the Internet topeople throughout the world, especially to the poor "who truly need it."

"Although this expenditure may seem high, we are living in an era when ourgreat-grandchildren may live in a world in which more than half of the plantspecies that exist now will be known only as specimens," said Raven.

Place more emphasis on alien-introduced plants and animals as a major causeof biodiversity losses. Studies of aliens and of the ways of controlling themshould be taken into account in evaluating the status of species in nature.

At the national level in every country around the world, maintain an activecensus of the condition of the country's plants, so that it will always beobvious which are well protected in nature -- or so abundant so as not to causeconcern -- and those that are rare and endangered.

Place special attention on conserving medicinal plants, important for thelivelihood of a great majority of the world's population.

Internationally fund an ongoing program of research on plant populationbiology and reproductive characteristics, generally, so that these areas can beunderstood properly and used as part of the world's overall preservation scheme.

"Recently, we have begun to realize how important the survival of pollinators isto the survival of healthy plant populations," said Raven.

Held only once every six years, the International Botanical congress last met inthe United States in 1969, when it was convened in Seattle, Washington. The XVIInternational Botanical Congress is being hosted by the Missouri BotanicalGarden in St. Louis.

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